Process of glazing artificial teeth



Sept. 6, 1932. L, M RRIS 1,876,015

PROCESS OF GLAZING ARTIFICIAL TEETH Filed Feb. 28. 1929 Patented Sept.6, 1932 UNITED STATES PATENT OFFICE CHARLES LEON MORRIS, OF COLUMBUS,OHIO, ASSIGNOR TO THE COLUMBUS DENTAL MANUFACTURING COMPANY, OFCOLUMBUS, OHIO, A CORPORATION PROCESS OF GLAZING ARTIFICIAL TEETHApplication filed February 28, 1929. Serial No. 343,504.

The object of this invention primarily ap plies to the dental art andthe object is to provide'a method and a means that will effectively andefficiently bake, glaze and stain artificial teeth.

Another important object of this invention is to provide a much moreeconomical method than has been previously employed.

Another important object of this invention is to provide a propercooling and annealing treatment.

In the drawing:

Figure 1 is a perspective view of a glazing furnace.

Figure 2 is a perspective view of a tray and cover.

Figure 3 is a perspective view of the tray.

Figure 4: is a longitudinal sectional view of the tray and cover.

Another important object is to provide a means whereby artificial teethmay be protected against specks or blemishes while being baked, glazed,stained or annealed.

The reference numeral 5 designates a furnace of suitable constructionfor carrying out my method of glazing dental porcelain, said furnacehaving a suitable closure 6.

In carrying out my method of glazing den tal porcelain I use a thinrefractory slab or base 7 having preferably, a seat 8 in its upper faceand extending entirely around the slab within the outer edge of theslab, in

which is seated the lower edge of a cover 9' also made thin andrefractory.

The slab and cover are made of material having high heat conductivityproperties and presents very little temperature lag which results in theheat intensity exerted on the enclosed ware (dental porcelain)registering substantially the same as the heat intensity immediatelysurrounding the refractory cover.

The cup or depression X in the cover is designed to hold a certainamount of gold. One may by looking through a peep hole in the kilnobserve the state of the gold from time to time, and when the gold hasbecome molten the operator knows that the glazing of thedental porcelainis finished.

The improved method practiced in carrying out this invention consists inemploying an electric resistance furnace having a nickel chromiumelement directly exposed, and in orderto protect the ware from theobjectional particles caused by spalling, a small, thin refractory coverhas been designed, which latter is inverted over the ware. The thinrefractory cover is composed of material having high heat conductivityproperties and presents very little temperature lag which results in theheat intensity exerted on the enclosed ware registering substantiallythe same as the heat intensity immediately surrounding therefractorycover.

This method further comprehends the simultaneous conveying of the wareand cover into and out of the furnace, so that the ware is at no timedirectly exposed to the detrimental spalling action of the heatingelement. The refractory coverin its broadest sense preferablycomprehends two parts, namely, a thin slab or baseportion and a coverportion proper. It may be thought of as a small removable mufflecompletely enclosing the ware; In applying this method the ware is firstplaced on the thin refractory slab, or base, while the latter is outsideof the furnace chamber. The refractory cover is then placed over theware and all parts are simultaneously conveyedinto the heat chamberwhere the ware receives the proper heat treatment. After the ware hashad sufficient heat treatment imposed'upon it, the base, cover and wareare simultaneously removed, the ware thus remaining covered andprotected.

This method further comprehends a'rapid, V

action promotes crystallization of the ware not entirely satisfactorybecause the chainand causes it to be weak and fragile structurally. Inthe past it has been common practice to slowly cool and anneal the warein the furnace chamber proper. This method is somewhat slow and rendersthe furnace chamber useless for the introduction of new ware.

Another method of cooling and annealing, which consists in having aseparate chamber for cooling, has been employed. This necessitates anextra amount of equipment and is her is usually at room temperature,which oftenimposes a shocker chill, to the ware, I 1 until theheat'radiation of the ware itself has CHARLES L. MORRIS.

raised the temperature within the chamber to I relatively near that ofthe rapidly. cooling ware. In other words, the'ware is cooled'to'orapidly during its first annealing period. 1 my improved method the wareis cooled at an even rate, yet elfici-ently and rapidly, due'to the highheat, conductivity property of the coverand base, and the wareisthoroughly protected from direct exposure to the atmosphere of theroom thus annealing it properly and adding materially to its strength.This method thus avoids'the Weakness and fragility due to impropercooling-methods.

This method compreh-endsthe use of several removable'mufiles, whichlatter are not expensive, and allows the operator to proceed withnewware to the furnace without a decided heat halt between heattreatments.

This improved method has a further ad vantage over the methods used inthe past in that the repair ofthe furnace iscomparatively inexpensive.It can readily be seen that when a platinum resistance elementburns outthatthe repair expense of such a furnace will be considerable in excessof the repair expense' in replacing with a new heat ing element composedofnickelchromium.

In. applying the improved method it has been found that the life of theresistance heating element of nickel chromium is equal to, and 111 someinstances greater than, the life of the platinum resistance element:that is to' say, the nickel chromium resistance element will stand asmuch, or more, service than the platinum resistance element at theirrespective service temperatures. I

What I claim is: I Y The method of glazing artificial teeth in anelectrical resistance furnaceemploying' a re sister exposed in thefurnace-chamber so as to protectthe tooth against 'spalling from theresistor and from injuryby atmospheric impurities or too sudden coolingafter glazing,

which method consists in enclosing the tooth in a covered dust-proofreceptacleof refractory material sufficiently thin to allow readypassage of heat therethrough and sufficiently refractory to withstandthe operating tern-' peratureof the furnace, disposingthe receptaclemthe furnacechamberand subjecting it

